With the development of high performance processing systems and improved communications links, transactions which in the past were conducted between parties face to face are instead being remotely conducted via electronic media. One of the most familiar of such systems is the automatic teller machine (ATM) which allows a bank customer to conduct a monetary transaction with his or her bank at times and locations more convenient than those usually provided by the bank's teller windows. Other communications systems such as electronic mail, audio/video teleconferencing, and computer networks are also helping relieve the expense and inconvenience which often results when various transactions must be conducted in person. While these systems have great advantages, they are still incapable of delivering to the end users all the information which can normally be exchanged, either explicitly or implicitly, during an in-person transaction. Further, because the amount and type of data which can be delivered is limited, the aesthetics of a given information exchange is correspondingly limited.
With these limitations in mind, recent efforts have been made to develop multimedia communications systems in which complete presentations of picture, voice and music can be provided to an end user. Not only would such systems generally allow for the communcation of more and different types of information, but would deliver such information in a more aesthetically complete format. The potential uses for such systems may include, for example, interactive applications such as movies-on-demand and home shopping.
One method of providing multimedia home shopping involves the exchange of media between the seller and shoppers via the postal system. For instance, a seller mails a CD-ROM or similar media containing a multimedia catalog to a shopper. The shopper then runs the CD-ROM catalog on the shopper's personal computer to peruse the goods or services offered for sale. A purchase can then be placed by telephone or by mail through a form generated from information stored on the CD-ROM. This option has several disadvantages. First, it may take up to several days for a CD-ROM catalog to reach the consumer. Second, CD-ROMs are relatively fragile, making mailing complicated and expensive. Third, each time the catalog is updated, a complete new CD-ROM typically must be mailed.
Another multimedia communications technique involves real-time video conferencing via personal computers. In this case, the personal computer of each party engaging in a conference includes a video camera, a microphone, speakers, a video capable display, and the circuit cards and software required to transmit voice and data. Disadvantageously, the required hardware is specialized and typically expensive. Further, no single standard has been recognized which limits the number of combinations of computers which can exchange information.
In Digital Simultaneous Voice and Data (DSVD) systems, voice and data are transmitted between computers on a single channel. The audio component is compressed in real-time at the transmitting terminal before transmission and then decompressed in real-time at the receiving terminal. The primary disadvantage of DSVD systems is that the real-time data compression operation requires substantial computing power. Hence, specialized modems with on-board digital signal processors are required which perform the compression/decompression operations thereby reducing the burden on the central processing unit. DSVD systems have the further disadvantage of requiring a fully digital link connecting the users.
Another current implementation alternates a connection between a voice call and a data call using a specialized voice/data modem protocol. While this system eliminates the processor bandwidth requirements of the DVSD modem, it also eliminates the capability of simultaneous delivery of voice and data.
In addition to the limitations of the available computer hardware and software, limitations on the available transmission (interconnection) media also constrain the implementation of interactive multimedia systems. One major obstacle is the limited bandwidth of the public telephone lines which currently are the most widely available and easily accessible interconnection media. Due to this limited bandwidth, the data transmission rates between terminals, and consequently the amount of data which can be exchanged, is severely impacted. Thus, most current data exchange schemes can only transfer the data for one media object at a time forcing the user interface to display (or play in the case of audio) only one media object at a time. Further, different types of media objects may require different bandwidths, resulting in inefficient use of the available transmission media. Interactive multimedia systems could be based on specialized transmission media such as cable or ISDN, but these are not widely available and require faster, specialized, interfaces.
Given the substantial advantages of multimedia presentations, namely the ability to communicate substantial amounts of information in an aesthetically pleasing fashion, the need has arisen for systems and methods for controlling and transferring multimedia presentations between a central processing system or server and a satellite system. In particular, such systems and methods should be capable of transferring multimedia data packages across limited bandwidth transmission media, such as the public telephone lines. Additionally, such systems and methods should enable the implementation of multimedia exchanges without requiring specialized hardware. Further, such systems and methods should be capable of utilizing a low bandwidth transmission medium to generate multimedia presentations including pictures, text, and music concurrently at the satellite in real-time. Preferably, these presentations can begin immediately after the connection between the server and the satellite has been established. Finally, while such systems and methods should be capable of use in a wide variety of applications, they should be particularly adapted for interactive applications, such as electronic home shopping.